Facebook on Friday disclosed that its systems had recently been targeted by an attack / Jeff Chiu AP

by Byron Acohido, USA TODAY

by Byron Acohido, USA TODAY

SEATTLE -- There are a few details about a breach of Facebook's network, disclosed by the social media giant today in a blog post.

The "sophisticated attack" was discovered by Facebook Security last month.

It occurred "when a handful of employees visited a mobile developer website that was compromised. The compromised website hosted an exploit which then allowed malware to be installed on these employee laptops."

Facebook's disclosure follows revelations of similar hacks of networks at The New York Times, Wall Street Journal, Twitter and the Federal Reserve, all in the past two weeks.

This is part of a trend of companies admitting they've been breached, limiting damage or theft caused by the attacks, then disclosing some details publicly.

Facebook says the laptops in question "were fully-patched and running up-to-date anti-virus software. As soon as we discovered the presence of the malware, we remediated all infected machines, informed law enforcement, and began a significant investigation that continues to this day."